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Paul, I've had this bike for two years now and put a total of 6,000 mikes on it with shaft/spline failure at 38,000 miles.
I guess my question at this point is- based on photographic evidence, which may not be enough evidence and I have not measured runout, do you think a new flywheel is necessary or do you think the failure is due to a lack of spline lubrication, or a combination of both? At $800-$1000 for a new input shaft and $500 for a new clutch pack, I'm not to excited to spend another $320 on a flywheel if not necessary.

I believe this bike spent the majority of its life in FL in obviously hot and potentially in sandy, gritty, and salty environs. Could this have exacerbated spline wear and lube breakdown?

Paul, I've had this bike for two years now and put a total of 6,000 mikes on it with shaft/spline failure at 38,000 miles.
I guess my question at this point is- based on photographic evidence, which may not be enough evidence and I have not measured runout, do you think a new flywheel is necessary or do you think the failure is due to a lack of spline lubrication, or a combination of both? At $800-$1000 for a new input shaft and $500 for a new clutch pack, I'm not to excited to spend another $320 on a flywheel if not necessary.

I believe this bike spent the majority of its life in FL in obviously hot and potentially in sandy, gritty, and salty environs. Could this have exacerbated spline wear and lube breakdown?

Strictly my opinion - Florida heat and sand isn't related to the failure. Almost certainly you have had radial run out. Otherwise, clutch systems run very dirty by their nature. Who knows if BMW even lubed this on initial assembly?

If you only ride 3,000 miles per year (like me on my 2000 R1100RT), and if it was my bike, I'd just put a new clutch disk in, and not replace anything else major. Lube it with a good antiseize such as Guard Dog (others have recommended it) or nickel based hi temp Neva Seize (my choice FWIW because that's what I have used before). I realize the shaft spline is worn, and most would want to replace it, but the clutch hub will soon wear such that most of the spline will once again be carrying the load giving you maybe an 80 percent life expectancy.

Be sure to use a clutch disk pilot when reassembling, or arrange to completely release the clutch while the engine-transmission bots are being tightened. After it is reassembled but before installing the starter, note the apparent spline backlash at the perimeter of the clutch disk. It should be less than a millimeter.

After you have driven it maybe 8,000 miles, remove the starter and again measure the backlash. It will be considerably more - maybe 1/4 inch - but don't panic until it reaches 3/8 inch or more. It is hard to say how much of your previous problem was lubrication or alignment error.

In the meantime, maybe you might run into a used transmission ($300?) with a better input shaft. This would be a lot cheaper way to go. The misalignment will still be there, but more frequent checks and if necessary, relubing, will help calm your future fears. If it becomes necessary, maybe by then someone will have figured out a way to lube the spline thru the starter hole.

If you do tear the transmission apart and spend the $$$ on a new shaft, PM me & we'll see if we can gin up a way to measure the error.

i think that with a shaft failure at 38k miles, you likely have a misalignment between trans and engine housings. if it's just a lube issue, failure is more common in the 60K+ range, which is why Paul G recommends 40K intervals for periodic lubing.

i think that with a shaft failure at 38k miles, you likely have a misalignment between trans and engine housings. if it's just a lube issue, failure is more common in the 60K+ range, which is why Paul G recommends 40K intervals for periodic lubing.

If this is indeed the case would there be any value to flywheel replacement?

Why not measure the flywheel flatness with a dial indicator? That would quickly answer the question of whether a new flywheel is needed, no opinion involved.

I don't have a dial indicator and with two boys in College I'm trying to avoid the purchase of seldom used tools, like clutch alignment tool. But I can see in this situation where it might be a good investment. Can the flywheel be easily rotated in place?

I would check the flywheel for axial runout with a dial indicator. A quick search with Google found a few in the $25-$40 range that would be adequate for this purpose. You are not trying to get a highly accurate absolute value - you are looking for close to none. If the flywheel is not true it ought to be replaced. If it is then replacement is a waste of money.

This is an early failure - not one where the disk just finally wore out. So wear or warping of the pressure plate and clutch cover may not be a factor - or much of a factor. Visually look for wear or hot spots, and check for reasonable trueness by laying a straight edge across the steel faces looking of warping or a slightly concave shape. If they look good keep them.

Regardless of whether a bent flywheel is present, or there is a misalignment between the transmission shaft and engine shaft, or both, or neither, the lack of lubrication is a clear factor. For lubrication you need: extreme pressure (EP) rating, high tack (stickiness) so it stays in place, excellent anti-corrosion characteristics, and ability to resist high temperatures. This is not a chassis or ball joint application. I insist on a high "moly" (MSO2 - Molybdenum di-sulphide) content. I look for at least 25% moly by volume. That black moly grease at the NAPA or Auto Zone store is 3% to 5% moly so that is not the stuff. I used to mix my own - now I just get GD525 from Guard Dog Moly.

In my experience, I have sometimes replaced a disk and not a shaft - expecting to get some reduction in life as they wear back in together, but worth it given the parts and labor to install a new shaft. This is a judgement call. It is usually "best" to replace everything but we can't always justify doing what is "best" when what is necessary is something less. But do recognize that putting a new part to wear against a partly worn part means the assembly won't last as long as if all the parts were new.

Paul Glaves - "Big Bend", Texas U.S.A
"The greatest challenge to any thinker is stating the problem in a way that will allow a solution." - Bertrand Russellhttp://web.bigbend.net/~glaves/

I use this bike primarily as a commuter in the summer (based on current weather pattern this will be limited to July) 3k to 4k miles per year. If I replace the clutch plate only and when considering the condition of the shaft, what kind of life expectancy can I reasonably expect?

As much as I would like to use the "best" repair methodology, I'm really leaning towards the clutch plate replacement direction (thanks nrpetersen!) if the shaft has enough metal to hold up. I have seen a "modified clutch plate" offered by Bruno's in Ontario, Canada. And I'm wondering if this plate may offer more longevity than an OEM plate?

I will most certainly check the flywheel for runout. Thanks for all the advice!

Hello everybody.
I guess I am the epicenter of the input shaft splines now. I have been reading (and posting) in a few other threads and the short story is that for the past 7-8 years discussion has been going on that boils down to these facts (or assumptions)

Input splines fail and they always fail with the same pattern (the famous picture posted by Anton I believe)

Shaft too short -----longer shaft designed by GSAddict (hello again, good to see you back) , one part no repeat failure.
Shaft too short ---- modified clutch hub -- unknown number of parts , unknown results.

Unknown root cause (assumed to be flywheel issue) --- replacement of the flywheel and all clutch components and input shaft ---practiced by Anton (sorry for going by the first name but I don't want to butcher your last, people do it to me all the time) -- unknown number of repairs --- no repeat complaints.

So if you are in this situation you have following options

1. Replace just the clutch plate. Cost $170. Without a doubt the fastest and cheapest solution, but as we all agree will not last, maybe fix and sell (ethical issues)
2. Replace input shaft and clutch parts . Cost about $1000 parts, another $1000 or so labor, should last as long as the first time.

3. Replace all as option 2 + flywheel, additional $300 or so added to option 2. Should be OK for long term according to Anton but no official data.
4. Install modified clutch hub, now we split the decision tree again.

4a. Install all as 3 +modified clutch hub, additional $400 to option 3 costs but it should be OK since there is no reason to believe that full shaft engagement can make it worse and if option 3 works that this one is even better.

4b. Install only modified clutch hub and leave everything else as is. Now, this is an option that has possibilities, the only snag is high cost of modified clutch. $600 and maybe it takes a while to get, I have no official data.
I am leaning towards this one for the following reason.
If modified clutch is installed than the worn parts of the spline are located in the middle of the new clutch hub and not on the edge so that should take the stress away from the compromised area. And people that are saying that 75% engagement is enough can not complain about this one since even with a chewed up splines we are at more than 75% surface area coverage. Additionally, you are buying yourself much more time then by just putting stock clutch disk back in.
If there is something I am missing please let me know but from extensive reading I have conducted this about sums it up as far as the options go.

Sorry for the huge post but I find it much easier to dump all my thought at once and not worry about grammar or sentence structure.

Hello everybody. I guess I am the epicenter of the input shaft splines now. I have been reading (and posting) in a few other threads and the short story is that for the past 7-8 years discussion has been going on that boils down to these facts (or assumptions)

Input splines fail and they always fail with the same pattern (the famous picture posted by Anton I believe)

I wonder if those pix might all be of the same shaft from different angles?

I don't know that the alignment error correction was or even should be successful as the possibility of engine main bearing clearance wasn't checked. I don't know the history of the R1100 I worked on, and that one did have a lot of main bearing clearance.

Originally Posted by esmir.celebic

Shaft too short -----longer shaft designed by GSAddict (hello again, good to see you back) , one part no repeat failure.
Shaft too short ---- modified clutch hub -- unknown number of parts , unknown results.

I don't think it's worth modifying these parts tho.

Originally Posted by esmir.celebic

Unknown root cause (assumed to be flywheel issue) --- replacement of the flywheel and all clutch components and input shaft ---practiced by Anton (sorry for going by the first name but I don't want to butcher your last, people do it to me all the time) -- unknown number of repairs --- no repeat complaints.

I don't think a warped flywheel would cause serious spline loading during operation as the disk will center itself as necessary every engagement.

Originally Posted by esmir.celebic

So if you are in this situation you have following options

1. Replace just the clutch plate. Cost $170. Without a doubt the fastest and cheapest solution, but as we all agree will not last, maybe fix and sell (ethical issues)

(1) Above) That's what I'd recommend.

Originally Posted by esmir.celebic

2. Replace input shaft and clutch parts . Cost about $1000 parts, another $1000 or so labor, should last as long as the first time.

3. Replace all as option 2 + flywheel, additional $300 or so added to option 2. Should be OK for long term according to Anton but no official data.
4. Install modified clutch hub, now we split the decision tree again.

4a. Install all as 3 +modified clutch hub, additional $400 to option 3 costs but it should be OK since there is no reason to believe that full shaft engagement can make it worse and if option 3 works that this one is even better.

4b. Install only modified clutch hub and leave everything else as is. Now, this is an option that has possibilities, the only snag is high cost of modified clutch. $600 and maybe it takes a while to get, I have no official data.

I am leaning towards this one for the following reason.
If modified clutch is installed than the worn parts of the spline are located in the middle of the new clutch hub and not on the edge so that should take the stress away from the compromised area. And people that are saying that 75% engagement is enough can not complain about this one since even with a chewed up splines we are at more than 75% surface area coverage. Additionally, you are buying yourself much more time then by just putting stock clutch disk back in.
If there is something I am missing please let me know but from extensive reading I have conducted this about sums it up as far as the options go.

One could do a simple eyeball check for a bent flywheel with a simple bent wire pointer probe. But remember there is probably legitimate axial clearance in the crankshaft bearing system that could look like flywheel run out. Press the flywheel in one direction during the check at least. Some face run out (like 1/32 inch max at the flywheel OD) wouldn't scare me.

I would also do a qualitative check for radial clearance in several directions on the engine's rear main bearing to see if the alignment error has worn the main bearing excessively. This could be done by radially prying on the flywheel with a screwdrive, and it is amazingly obvious on the one I worked on. If necessary, I suppose one could use a set of feeler gages if there wasn't access to a dial indicator - especially if there was an obvious bad direction of maximum clearance. The original factory clearance is only .002 inch, and anything over say .006 would reason to worry about being able to maintain oil pressure when hot.